TY  - JOUR
TI  - Localization of a high molecular weight form of DNA topoisomerase I in amphibian oocytes.
AU  - Gebauer, D
AU  - Mais, C
AU  - Zinger, K
AU  - Hock, R
AU  - Lieb, B
AU  - Scheer, U
T2  - The International Journal of Developmental Biology
AB  - Xenopus oocytes express a 165 kDa variant of DNA topoisomerase I (topo I) as opposed to the canonical 110 kDa form of somatic cells (Richard and Bogenhagen, Dev. Biol. 146: 4-11, 1991). By immunofluorescence microscopy using variant-specific antibodies we show that this high molecular weight form is associated with lampbrush chromosome loops and the inner regions of the amplified nucleoli. Inhibition of topo I-activity by either Camptothecin-treatment or microinjection of neutralizing antibodies resulted in loop retraction and the condensation of chromosomes and amplified nucleoli. These data indicate that the oocyte-specific 165 kDa form of topo I is involved in transcriptional processes mediated by RNA polymerase I and II and is therefore functionally equivalent to the somatic cell 110 kDa counterpart.
PY  - 1996
VL  - 40
IS  - 1
SP  - 239
EP  - 244
J2  - Int. J. Dev. Biol.
LA  - en
SN  - 0214-6282
SN  - 1696-3547
UR  - https://ijdb.ehu.eus/article/8735934
Y2  - 2024/11/05/13:20:08
ER  -